memblockq.h

#ifndef foomemblockqhfoo#define foomemblockqhfoo/*** This file is part of PulseAudio. Copyright 2004-2006 Lennart Poettering PulseAudio is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. PulseAudio is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with PulseAudio; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.***/#include <sys/types.h>#include <inttypes.h>#include <pulsecore/memblock.h>#include <pulsecore/memchunk.h>#include <pulse/def.h>/* A memblockq is a queue of pa_memchunks (yepp, the name is not * perfect). It is similar to the ring buffers used by most other * audio software. In contrast to a ring buffer this memblockq data * type doesn't need to copy any data around, it just maintains * references to reference counted memory blocks. */typedefstruct pa_memblockq pa_memblockq;
/* Parameters: - idx: start value for both read and write index - maxlength: maximum length of queue. If more data is pushed into the queue, the operation will fail. Must not be 0. - tlength: the target length of the queue. Pass 0 for the default. - base: a base value for all metrics. Only multiples of this value are popped from the queue or should be pushed into it. Must not be 0. - prebuf: If the queue runs empty wait until this many bytes are in queue again before passing the first byte out. If set to 0 pa_memblockq_pop() will return a silence memblock if no data is in the queue and will never fail. Pass (size_t) -1 for the default. - minreq: pa_memblockq_missing() will only return values greater than this value. Pass 0 for the default. - maxrewind: how many bytes of history to keep in the queue - silence: return this memchunk when reading unitialized data*/
pa_memblockq* pa_memblockq_new(
int64_t idx,
size_t maxlength,
size_t tlength,
size_t base,
size_t prebuf,
size_t minreq,
size_t maxrewind,
pa_memchunk *silence);
void pa_memblockq_free(pa_memblockq*bq);
/* Push a new memory chunk into the queue. */int pa_memblockq_push(pa_memblockq* bq, const pa_memchunk *chunk);
/* Push a new memory chunk into the queue, but filter it through a * pa_mcalign object. Don't mix this with pa_memblockq_seek() unless * you know what you do. */int pa_memblockq_push_align(pa_memblockq* bq, const pa_memchunk *chunk);
/* Manipulate the write pointer */void pa_memblockq_seek(pa_memblockq *bq, int64_t offset, pa_seek_mode_t seek);
/* Return a copy of the next memory chunk in the queue. It is not * removed from the queue. There are two reasons this function might * fail: 1. prebuffering is active, 2. queue is empty and no silence * memblock was passed at initialization. If the queue is not empty, * but we're currently at a hole in the queue and no silence memblock * was passed we return the length of the hole in chunk->length. */int pa_memblockq_peek(pa_memblockq* bq, pa_memchunk *chunk);
/* Drop the specified bytes from the queue. */void pa_memblockq_drop(pa_memblockq *bq, size_t length);
/* Rewind the read index. If the history is shorter than the specified length we'll point to silence afterwards. */void pa_memblockq_rewind(pa_memblockq *bq, size_t length);
/* Test if the pa_memblockq is currently readable, that is, more data than base */
pa_bool_t pa_memblockq_is_readable(pa_memblockq *bq);
/* Return the length of the queue in bytes */size_t pa_memblockq_get_length(pa_memblockq *bq);
/* Return how many bytes are missing in queue to the specified fill amount */size_t pa_memblockq_missing(pa_memblockq *bq);
/* Return the number of bytes that are missing since the last call to * this function, reset the internal counter to 0. */size_t pa_memblockq_pop_missing(pa_memblockq *bq);
/* Directly moves the data from the source memblockq into bq */int pa_memblockq_splice(pa_memblockq *bq, pa_memblockq *source);
/* Set the queue to silence, set write index to read index */void pa_memblockq_flush_write(pa_memblockq *bq);
/* Set the queue to silence, set write read index to write index*/void pa_memblockq_flush_read(pa_memblockq *bq);
/* Ignore prebuf for now */void pa_memblockq_prebuf_disable(pa_memblockq *bq);
/* Force prebuf */void pa_memblockq_prebuf_force(pa_memblockq *bq);
/* Return the maximum length of the queue in bytes */size_t pa_memblockq_get_maxlength(pa_memblockq *bq);
/* Get Target length */size_t pa_memblockq_get_tlength(pa_memblockq *bq);
/* Return the prebuffer length in bytes */size_t pa_memblockq_get_prebuf(pa_memblockq *bq);
/* Returns the minimal request value */size_t pa_memblockq_get_minreq(pa_memblockq *bq);
/* Return the base unit in bytes */size_t pa_memblockq_get_base(pa_memblockq *bq);
/* Return the current read index */
int64_t pa_memblockq_get_read_index(pa_memblockq *bq);
/* Return the current write index */
int64_t pa_memblockq_get_write_index(pa_memblockq *bq);
/* Change metrics. Always call in order. */void pa_memblockq_set_maxlength(pa_memblockq *memblockq, size_t maxlength); /* might modify tlength, prebuf, minreq too */void pa_memblockq_set_tlength(pa_memblockq *memblockq, size_t tlength); /* might modify minreq, too */void pa_memblockq_set_prebuf(pa_memblockq *memblockq, size_t prebuf); /* might modify minreq, too */void pa_memblockq_set_minreq(pa_memblockq *memblockq, size_t minreq);
void pa_memblockq_set_maxrewind(pa_memblockq *memblockq, size_t maxrewind); /* Set the maximum history size */void pa_memblockq_set_silence(pa_memblockq *memblockq, pa_memchunk *silence);
/* Call pa_memchunk_willneed() for every chunk in the queue from the current read pointer to the end */void pa_memblockq_willneed(pa_memblockq *bq);
/* Check whether the memblockq is completely empty, i.e. no data * neither left nor right of the read pointer, and hence no buffered * data for the future nor data in the backlog. */
pa_bool_t pa_memblockq_is_empty(pa_memblockq *bq);
/* Drop everything in the queue, but don't modify the indexes */void pa_memblockq_silence(pa_memblockq *bq);
/* Check whether we currently are in prebuf state */
pa_bool_t pa_memblockq_prebuf_active(pa_memblockq *bq);
/* Return how many items are currently stored in the queue */unsigned pa_memblockq_get_nblocks(pa_memblockq *bq);
#endif